Tuesday, April 12, 2016

EWS Basics : Reporting on the Age of Items in a Folder

One of the more common questions I get is around some of the EWS Item Age scripts I've written in the past. If we take the script I introduced in the first Basics post with some easy modifications we can turn this script that already enumerates all the Items in a folder into a script that will report on age of the Items in a folder. So in this post I'm going to try to explain a little better the changes that you would need to make.

EWS Changes

The EWS changes that need to be made to the basics script are to the Propertyset that is used in the FindItems Operation. A PropertySet in EWS basically tells Exchange which properties you want to be returned. So to make this script as efficient as possible we want to restrict Exchange to just returning the Size and DateTime the messages where received or created. So these are the only changes that are needed for the EWS side

$ivItemView =  New-Object Microsoft.Exchange.WebServices.Data.ItemView(1000) 
$ItemPropset= new-object Microsoft.Exchange.WebServices.Data.PropertySet([Microsoft.Exchange.WebServices.Data.BasePropertySet]::IdOnly)
$ivItemView.PropertySet = $ItemPropset


When your reporting on the age of Items your basically aggregating the part of the Date/Time a Message was received. To do the aggregation in this script I'm just using a Hashtable which there is a good description of at https://technet.microsoft.com/en-us/library/ee692803.aspx . The way I'm using them to aggregate the number of Messages and the size of the messages for the Year a Message was received in. To get the Year a message was received in the item enumeration section of the script I'm using this simple function

$dateVal = $null
if($Item.TryGetProperty([Microsoft.Exchange.WebServices.Data.ItemSchema]::DateTimeReceived,[ref]$dateVal )-eq $false){
 $dateVal = $Item.DateTimeCreated
What this does is loads the DateTimeReceived property into the $dataVal variable and if that property isn't available (eg the message maybe a draft) it uses the DateTime created property.

Once we have this value its just a matter of firstly using the Year property of the (DateTime) Class and then we aggregate this value with the Hashtable. In the Values collection of the HashTable I'm using a Custom object (see https://technet.microsoft.com/en-us/magazine/hh750381.aspx) that does the aggregation part.  eg

 $rptCollection[$dateVal.Year].TotalNumber += 1
 $rptCollection[$dateVal.Year].TotalSize += [Int64]$Item.Size
 $rptObj = "" | Select Year,TotalNumber,TotalSize
 $rptObj.TotalNumber = 1
        $rptObj.Year = $dateVal.Year
 $rptObj.TotalSize = [Int64]$Item.Size

At the end of this we can just write the HashTable Values collection back to output Pipeline using write-object taking advantage of the sort-object cmdlet to make sure the values are sorted descending by Year

Write-Output $rptCollection.Values | Sort-Object -Property Year -Descending

I've put a copy of this script on GitHub here https://github.com/gscales/Powershell-Scripts/edit/master/GetItemAgeFromItemsInFolder.ps1

An example of running this script would look like